标题： 测试甲醇麻线环追踪恒星盘假设：高分辨率近红外和中红外成像 显示英文标题

标题： Testing the Hypothesis that Methanol Maser Rings Trace Circumstellar Disks: High Resolution Near-IR and Mid-IR Imaging

摘要： 包含6.7 GHz 甲醇脉泽发射的区域的兆秒级甚长基线干涉测量图导致了环状分布脉泽斑点的近期发现，并提出了它们可能正在追踪形成中的高质量恒星周围星周盘的合理假设。 我们的目标是通过在高空间分辨率下的近红外和中红外成像来测试这一假设，并将观测到的发射与从脉泽环几何形状推断出的预期红外形态进行比较。 在近红外波段，我们使用了Altair/NIRI的Gemini北自适应光学系统；而在中红外波段，我们则使用了Gemini南仪器T-ReCS与超分辨率技术的结合。 由此产生的图像在近红外和中红外波段的分辨率为大约150毫角秒。 我们讨论了围绕年轻且质量较大的吸积（原）恒星周围的星周物质分布情况，并假设脉泽来自星周盘内时，不同脉泽环取向的预期红外发射几何结构。 基于我们样本中四个目标的观测红外发射几何结构以及与脉泽环相关的高质量年轻恒星天体的SED建模结果，我们没有发现支持甲醇脉泽环存在于星周盘这一假设的有力证据。 显示英文摘要

摘要： Milliarcsecond VLBI maps of regions containing 6.7 GHz methanol maser emission have lead to the recent discovery of ring-like distributions of maser spots and the plausible hypothesis that they may be tracing circumstellar disks around forming high mass stars. We aimed to test this hypothesis by imaging these regions in the near and mid-infrared at high spatial resolution and compare the observed emission to the expected infrared morphologies as inferred from the geometries of the maser rings. In the near infrared we used the Gemini North adaptive optics system of Altair/NIRI, while in the mid-infrared we used the combination of the Gemini South instrument T-ReCS and super-resolution techniques. Resultant images had a resolution of approximately 150 mas in both the near-infrared and mid-infrared. We discuss the expected distribution of circumstellar material around young and massive accreting (proto)stars and what infrared emission geometries would be expected for the different maser ring orientations under the assumption that the masers are coming from within circumstellar disks. Based upon the observed infrared emission geometries for the four targets in our sample and the results of SED modeling of the massive young stellar objects associated with the maser rings, we do not find compelling evidence in support of the hypothesis that methanol masers rings reside in circumstellar disks.